Description

This document represents the third refined working proposal for the tire wear and consumption module of the HDM-4 model under the International Study of Highway Development and Management Tools (ISOHDM). Building upon earlier iterations, this technical paper incorporates extensive empirical validation data collected from field experiments across developing and developed countries, including trials conducted in tropical, sub-tropical, and temperate environments. The report refines the mathematical relationships governing tread volume loss as a function of pavement roughness, macrotexture depth, road curvature, superelevation, vertical grade, and vehicle speed. Special focus is placed on establishing robust calibration methodologies for commercial vehicle fleets operating under heavy axle load conditions and variable tire maintenance standards, such as improper inflation pressure or wheel misalignment. Algorithms are presented for calculating carcass wear, retreadability rates, and catastrophic tire failure probabilities, enabling a complete life-cycle cost assessment of vehicle tires. Practical guidance is provided on default parameter values for modern radial tire designs compared to legacy bias-ply tires, ensuring that the model accurately reflects contemporary fleet characteristics and rubber compound formulations. This refined specification serves as the primary technical blueprint for coding the finalized tire consumption algorithms within the HDM-4 software suite for global highway economic appraisals. Overall, the report emphasizes rigorous empirical validation, standardized data acquisition protocols, and modular integration into the broader Highway Development and Management analytical engine. By combining physical principles with statistical calibration across international trial sites, this working paper provides a robust theoretical and practical baseline for highway authorities to evaluate long-term infrastructure policy